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Ketamine seen as promising new depression drug

Mounting evidence suggests the party drug and anesthetic is an effective depression treatment, but it's still not available in Canada.

Patrick Cameron has suffered from depression for years but recently travelled to New York CIty for a new kind of treatment: ketamine (horse tranquilizer), administed intravenously. Cameron is now a believer, saying he's finally found the answer to his pain. (David Cooper / Toronto Star) | Order this photo

Patrick Cameron noticed a change in his brain on the third day of his treatment. The morning sun streamed through the trees above the Manhattan sidewalk, and for the first time in a long time, there was space in his thoughts to appreciate it.

“My mind wasn’t crowded up,” said the 31-year-old Torontonian who’s been dogged by depression since adolescence. “I could just watch it and not have a thud of negative thoughts.”

It was a welcome feeling that lingered for days, an elusive turnaround that Cameron credits to the innovative therapy he travelled to New York City to receive: a daily intravenous dose of ketamine, a popular club drug and widely used anesthetic that researchers say has the potential to help people like Cameron, with intractable cases of depression.

“This is the only thing that’s worked,” said Cameron. “I feel more like myself — much less pain and much less suffering.”

Over the past decade, studies have suggested ketamine — known in some party circles as “Special K” — can effectively treat depression, especially when compared with the commonly used serotonin selective reuptake inhibitors (SSRIs). In a 2012 review of this research in the prestigious journal
Science
, Yale professors George Aghajanian and Ronald Duman said the emerging ketamine treatment is “arguably the most important discovery” — when it comes to depression — “in half a century.”

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That’s no exaggeration, said Arun Ravindran, a University of Toronto psychiatry professor and chief of mood and anxiety disorders at Toronto’s Centre for Addiction and Mental Health (CAMH).

“The data has been building up in the last 10, 12 years,” he told the Star. “It’s very promising. Very, very promising.”

As it stands now, Health Canada hasn’t licensed the use of ketamine for depression treatment, though there are ongoing clinical studies at the University of Ottawa and elsewhere examining its use. That means people like Cameron, who haven’t had success with any other treatment and are reticent to try electro-convulsion therapy, have to head south and fork over thousands of dollars to try ketamine infusions.

“I understand the need for caution, because it is a street drug and can be addictive,” said Cameron, who paid $3,000 for six IV infusions of the drug. “I’m just worried about access to my treatment.”

Ravindran said he expects the treatments will become available as research progresses. It also remains costly and “inefficient,” because the positive effects of ketamine treatments seem to only last a few days, and could offer diminishing returns when repeated over time, he said.

A coming study that Ravindran is leading will look at other ways to take the drug: nasally or orally instead of intravenously, he said.

“We need to find something that will make the effect of ketamine more sustained.”

Still, there’s already reason for excitement, he said. This hope for ketamine stems from how hard it remains to effectively treat cases of major depression. Regularly prescribed SSRIs, such as Prozac and Zoloft, can take weeks or even months to kick in. Even then, said Ravindran, about 20 per cent of patients don’t see any effect from these drugs.

Ketamine, on the other hand, “seems to be addressing these issues well,” said Ravindran. It is very quick acting — effects are typically seen within 48 hours — and it is proving effective for people resistant to the currently predominant treatments. Some studies have concluded 50 to 75 per cent of these patients have seen benefits from ketamine, Ravindran said.

“It’s much faster than regular antidepressants and works when regular antidepressants don’t seem to work,” he said.

Ravindran said the reason for this is that ketamine seems to more effective at “enhancing” receptors in the brain that are blocked up when someone has depression. “(Ketamine) repairs the damage that has happened to the brain cells because of depression.”

In terms of side effects, the primary concern is what Ravindran calls the “relaxed dissociated state” that comes during the ketamine treatment and disappears within a few hours. Essentially, the patient is tripping out (Cameron said he felt “spacey” and detached). This can be frightening for some people, said Ravindran, who added that he feels such concerns are outweighed the power of ketamine to soften depression quickly.

“When someone is going to kill themselves, this is a relatively minor problem,” he said.

As for Cameron, he said he might return to the U.S. for treatment in a few months, as the clinic suggested, hoping to keep his depression at bay until he’s able to receive the therapy in his home country.

“This might actually be over,” he said. “I might have finally found the answer.”

Correction - August 26, 2014:
This article was edited from a previous version that misspelled Arun Ravindran's surname.

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